1. Field of the Invention
The present invention relates to a magnetic write head, and more particularly, to a magnetic write head having a structure in which a main pole is surrounded by a side shield, and a method of manufacturing the magnetic write head.
2. Description of the Related Art
With the advent of industrialization and an information-oriented society, the amount of information handled by individuals or organizations has sharply increased. It is possible to access the Internet where various kinds of information can be obtained. Also, computers with a fast data processing speed and a large data storing capacity have been widely distributed. Central processing unit (CPU) chips and computer peripheral devices are continuously improved to increase the data processing speed of the computer. To improve the data storing capacity, a variety of information storing media, for example, hard disks, need to be highly densified.
Recently, a variety of recording media have been introduced to meet these needs. Most recording media are magnetic recording media using a magnetic layer as a data recording layer, and such magnetic recording media can be classified into a horizontal magnetic recording method and a vertical magnetic recording method according to a data recording method.
The horizontal magnetic recording method is used to record data such that the magnetization direction of a magnetic layer is aligned parallel to the surface of the magnetic layer. The vertical magnetic recording method is used to record data such that the magnetization direction of a magnetic layer is aligned perpendicular to the surface of the magnetic layer. The vertical magnetic recording method is much more advantageous as compared to the horizontal magnetic recording method in view of the data recording density.
In a magnetic write head using the vertical magnetic recording method, to increase a recording density, it is important to improve a track density and a linear recording density. In order to improve the linear recording density, a magnetic field gradient of a magnetic write head needs to be increased. To this end, a recording medium having a dual layer structure in which a lower portion of the recording medium is coated with a soft magnetic underlayer is used. However, to achieve a recording density greater than 200 Gb/in2, a larger magnetic field gradient is needed. To improve the track density, a track width of a magnetic write head needs to be manufactured more accurately. However, it is a problem since an effective track width substantially recorded on the recording medium increases as compared to a geometric track width designed on the magnetic write head.
To address the above-described problem, a magnetic write head having a structure in which a wrap around shield is formed around a main pole has been developed. The wrap around shield has a merit in that the effective track width is decreased by increasing the magnetic field gradient in a track width direction, that is, a cross track direction. However, for the wrap around shield, paths through which the magnetic flux of the main pole leaks toward a return yoke are diverse so that a magnetic flux density in a trailing edge of the main pole decreases. Thus, a linear recording density in a track following direction, that is, a downtrack direction, is decreased.